High energy perspectives

(and conclusions)

Philippe FerrandoAPC Laboratory (UMR 7164) - Service d’Astrophysique CEA/Saclay

APC Conference High Energy Phenomena in the Galactic Center June 17, 2005

The Galactic Centre : an exciting and growing field

Exciting :

• closest look we can have to a Super Massive Black Hole and its complex surroundings in the Universe - Potential link with more distant AGNs

• potentially harboring dark matter, UHE cosmic-ray accelerator…

Growing :

New high quality high energy data :

• X-rays [0.1–10 keV] Chandra & XMM–Newton 1999 -…

• -rays [0.02-10 MeV] Integral 2002 -

• TeV -rays [0.1–20 TeV] HESS 2003 -

Multi Wavelength Campaigns with radio and NIR

Chandra & XMM–Newton

Angular resolution :

resolving this complex region, and measuring the quiescent spectrum of SgrA*

High throughput : detailed spectro-imaging up to 10 keV

Chandra and XMM–Newton

Sensitivity : acces to short time variabilityG

alac

tic L

atitu

de

X-ray flares from SgrA*, look for periodicity…

INTEGRAL

Sensitivity and angular resolution : mapping this complex region

• IBIS/ISGRI mosaics in different energy bands: spectrum 20-120 keV

• Possible shift of the central source between Sgr A and 1E1743

20-30 keV

40-60 keV

30-40 keV

60-85 keV

HESSSensitivity, angular resolution, large Field of View

H.E.S.S. Preliminary

But questions still open…

What makes the 6.4 keV line ?

Nature of hot component ? Origin of the large scale 511 keV line ?

But questions still open…

IntegralIntegral

How many sources ? Spectrum of SgrA* ?

Are Ultra High Energy Cosmic Rays accelerated at the GC ?

What can we count on for sure ?

Gamma-ray sources and UHECR connection

AGASA excess map in the a posteriori energy band [1017.9 – 1018.3] eV

15°

GC

Completion in 2006 Unprecedented statistics expected

Angular resol. 0.5–1°

GC and AGASA/Sugar prime targets

?

AUGER

What can we count on for sure ?

Gamma-ray - Neutrinos connection

ANTARES

Completion in 2007

Max of signal expected @ ~ 10 TeV

Very low bckgd for point sources

Angular resol. @ 10 TeV ~ 0.2°

Expected rate (HESS) very low 0.02 evt/year

but surprises possible…

Clear need for a km3 experiment in a longer term

What can we count on for sure ?

AGILE gamma-ray telescope

Small ASI mission - launch date early 2006

Anticoincidence

SuperAGILE

Si tracker

Mini-Calorimetre

GRID : E-range : 30 MeV – 30 GeVFoV 2.5 sr 36 arcmin @ 1 GeV

Improve EGRET error box radius by a factor of 2

What can we count on for sure ?

GLAST/LAT EGRET

E range : 0.02 -300 GeV 0.02-30

E resolution : 10 % 10 %

Eff. Area : 8000 cm2 1500

Field of view > 2 sr 0.5 sr

Ang. Resol. ~ 3o @ 100 MeV 5.8°

~ 0.15o > 10 GeV

Sensitivity <6 x 10-9 cm-2 s-1 ~ 10-7

Source locat. 0.5 - 5 arcmin 5–30

The GLAST mission : launch mid 2007

Orders of magnitude improvement upon EGRET

What can we count on for sure ?

Upgrade : HESS II

• Lower threshold to extend the energy-range in mono-telescope mode

• Better sensitivity at high energies in stereo

Reduce GC source position uncertainty

now 4'' ± 10''stat ± 20''syst from Sgr A* (1 pc)

Atmospheric Cerenkov (stress on HESS but also MAGIC, VERITAS,

CANGAROO)

What can we count on for sure ?

Full spectral coverage in

gamma-rays !

• Connection space-ground

• Variability

And in a longer term ?

An absolute necessity : get the angular resolution and the sensitivity down by orders of magnitude above 10 keV

XMM-Newton GC Survey 0.3-9 keV0.0°

0.0°

0.0° 359.0°1.0°

INTEGRAL GC Survey 20-40 keV

(Bel

ange

r et

al 2

005,

in p

rep.

)

(

Dec

ourc

helle

et

al.

2003

)

Sgr A

Sgr B2

The 10 keV sensitivity gap reason

0.1–10 keV : focusing opticsSpatial resolution : 15 arcsecHigh signal to noise

XMM–Newton

15 keV–10 MeV : coded masksSpatial resolution : 12 arcminModerate signal to noise

INTEGRAL

The necessary future : use focusing optics as in longer wavelengths

In hard X-rays : feasible on a large energy range by extension of the « usual » soft X–rays techniques

Focusing using a grazing incidence nested shells Wolter I mirror

• Long focal length for high reflectivity at high energy

Projects NuSTAR and SIMBOL-X

Basically : long focal length telescope, using grazing incidence X–ray optics, with mirror and detectors mounted on two different spacecraft in formation flying.

Characteristics

Energy range :0.5–70 keV

Resolution : < 130 eV @ 6 keV, 1 % @ 60 keV

Angular resol. : < 30 arcsec (local. < 3 arcsec)

Effective area : > 550 cm2 E < 35 keV 150 cm2 @ 50 keV

Sensitivity : 5 10-8 ph/cm2/s/keV (E < 40 keV)

(5 , 100 ks, E = E/2)

The Simbol-X mission

Optics (nominal)

• Direct heritage from XMM–Newton

• Long focal length for high reflectivity at high energy

• Nickel shells with single layer Pt coating, obtained by well proven electroforming replication method

• Low mass obtained via a reduced thickness of shells

: ~ 30’’ HEWFOV : ~ 6 arcmin580 cm2 @ 30 keV

Shell diameters : 290 to 600 mmFocal length : 30 mAngles : 0.07° to 0.142°Shell thickness : 0.12 to 0.30 mmNumber of shells : 100Total mass : 213 kg

CdZnTe

SDD

< 17 keV > 17 keV

Low energy detector (450 m Silicium)

High energy detector (2 mm Cd(Zn)Te)

Optical filter (0.1 m Al)

Anticoincidence (BGO)

Requirements

• Pixel size of ~ 500 m (gives good oversampling of the 4.4 mm PSF)

• Full diameter of focal plane : 6 cm

• Fast response detectors for full anticoincidence scheme

• Avoid constraining cooling

• Low energy response down to 0.5 keV

• Good spectral resolution for Iron line

Focal plane

SDD CdZnTe

Sensitivity

1 arcmin diameter region, 1 Ms exposure, E = E/2

XMM INTEGRALSIMBOL-X

The central 2 degrees > 20 keV

today

1.0°

INTEGRAL GC Survey 20-40 keVSgr A

Sgr B2

0.0° 359.0°

in 2012with Simbol-

X

SIMBOL-X3 , 1 hour

Testing accretion models with SIMBOL-X

•Measurement of spectra for a large range of flare intensities

•Access to the high energy range, discriminating models

•Quiescent spectrum at ~ 40 keV

Liu & Melia, 2002

Galactic Centre Diffuse Emission

(Decourchelle et al. 04)

Galactic Centre seen by SIMBOL-X

Spectrum in a 1 arcmin2 regionExposure time = 84 ks

Simulation > 10 keV, 10 x 10 arcmin2

Total exposure = 300 ks

(A. Decourchelle & J. Ballet)

Simbol–X status

•Selected by CNES for phase 0 assessment (4 missions kept)

•Phase A start, autumn 2005 (2 missions kept)

•Selection end 2006 (1 mission kept)

•Consortium led by France with a strong Italian involvment, and a firm participation of Germany

•Mission proposed early 2004 to CNES in response to a call for scientific missions using spacecrafts in formation flying

•Launch date : 2012 - 2 years of science observations

Conclusions

The Galactic Centre

an exciting and growing field, with a rich future !

A lot of important results to come in the next years, but will not solve all questions

A deeper look possible early next decade with currently designed new generation of instruments